Lately, I've noticed vehicles with tires that are clearly not OEM (Original Equipment Manufacturer) in size. Some are so large, they barely fit in the wheelwell. I don't know about the width, but assume the same is true. As most people realize, this changes the dynamics of the vehicle (handling), the speedometer readings and start up and braking abilities. Do you follow the manufacturer's recommendations? If not, why?

Hi GrumpyCat. You said, "How can that be? If the manufacturer of your original tires is Goodyear then Goodyear makes tires in all sizes. All tire sizes offered by Goodyear would be OEM (Original Equipment Manufacturer, who we have used Goodyear as our example)." I tried to carefully word that statement by including the words 'OEM in size'. I didn't think using OEM would imply that any size tire made by a manufacturer would fit or should be used. That was NEVER my intent. The rest of your post show that you clearly understand the size issues.

Here was my thought when writing. In 1984, I considered buying two vehicles, a Lincoln Continental Town Car and a Mercury Grande Marquis LS. Both vehicles had the same size tires, but the Lincoln had Michelin and the Mercury had Firestone tires. The point of emphasis is they were the same size, but not the same manufacturer. Your use of OE (Original Equipment) would have been more correct. I thank you for pointing that out and will consider it in future posts. I try not to mislead Gas Buddies, or you, in my posts. Sometimes what seems the right way to say something, isn't always true.

I especially liked your comments about the 24" tires as I know someone who did much the same thing. Forgetting for the moment your well documented issues, I've often wondered how you get in and out of the vehicle?

Thanks again for differentiating OEM from OE. I should have known better. :-) MGY

Hi Das. Thanks for the very detailed answer to my questions. I can see why my wife had such a difficult time while living there. I believe her stay was the late 1970s through the early 1980s.

The transition seemed to be a bit like that in the United States. We too have a split system with liquids in liters and gallons and automobiles with MPH and also KPH. During our transition many car parts were both metric and SAE, but lately it has settled down to mostly metric or SAE. I owned a 2008 Chevrolet Equinox and a garage ruined five lug nuts. You'll like this! The threads were 7 mm, the actual nut was 3/4" and the decorative metal covering over the nut was 13/16". Yes they were special order through NAPA auto parts. Reading over your post several times it seems that Canada's transition was lengthy, over twenty years, and somewhat confusing.

I was stationed on Okinawa, Japan for nearly three years. Up to May 1972, the island was under American jurisdiction since 1945, but many of Japan's items such as vehicles were metric (I got a speeding ticket from the MPs due to not converting my KPH speedometer to MPH properly). In 1972, the monetary system was converted from the US Dollar to the Japanese Yen. In 1975, driving changed to the opposite side of the road.

It seems in all of these cases it is a lengthy and complicated process.

This should answer your question:The use of metric or imperial measurements varies by age and region. Canadians who have received only metric instruction in school (from the early 1970s) are more familiar with metric measurements. Though traditional units are commonly used for height and weight, and are often used for length, a general understanding of traditional units does not generally go much beyond that unless perhaps the user has spent a significant amount of time in the United States. However unlike in the rest of Canada, metrication in the Francophone province of Quebec has been more implemented and metric measures are more consistently used in Quebec than elsewhere in Canada. The use of imperial units is more common in rural areas in the rest of the country, where opposition to metrication was strongest, rather than in urban areas.

Titanic1985:Hi Das. I have a question. Is Montreal entirely metric?Heres a little history about Canada going Metric::

Canadian metrication began in January 1970 when the Liberal government led by Pierre Trudeau introduced the White Paper on Metric Conversion which was supported by the House Leaders of all political parties in the House of Commons. By 1975 metric product labelling began and weather forecasts were in metric. By the end of 1977 all road signs were metric and all new cars had metric odometers and speedometers.In 1978 timetables were established for the conversion of the sale of motor fuels, individually measured retail foods, and home furnishings. On 3 June 1979 Canadians were faced with a federal election. While Canadians were starting to become accustomed to metric the Liberal party had become unpopular for a number of reasons and thus the Progressive Conservatives under Joe Clark formed the new minority government. Part of the Conservative's platform was to make metrication voluntary. In January 1980 the deadline for metrication of home furnishings passes without enforcement.On 2 March 1980 Canadians again went to the polls and elected a Liberal majority government under Pierre Trudeau form. By January 1981 motor fuel and fabric sales were metricated.In January 1983 two Toronto gas station owners, Jack Halpert and Ray Christianson, were charged under the Weights and Measures Act for selling gasoline by the imperial gallon. The two gas station owners won their case in provincial court. While the decision was under appeal by the Attorney General of Canada, Mark MacGuigan; Judy Erola, Minister of Consumer and Corporate Affaris, the federal department responsible for implementing the Weights and Measures Act, placed a moratorium on the metrication of motor fuels, home furnishings, and individually measured foods. At this point in the metrication process both the metric and imperial systems were permitted but the metric value was required to be displayed more prominently than the imperial value.On 17 September 1984 the Progressive Conservatives led by Brian Mulroney formed a new majority government.In October 1984 the Ontario Court of Appeal decided that the litre must be used for the retail sale of gasoline.In November 1984 the new Conservative Consumer and Corporate Affairs Minister Michel Côté announces that his department will not prosecute violators of the metric laws but will ensure consumers are protected from fraud or inaccurate measuring whether it is in metric or imperial. In Jaunary 1985 the Mr. Côté announces that the metrication regulations were to be replaced with new regulations. In March 1985 the Metric Commision of Canada was disbanded and replaced by a small Metric Information Division in the department of Industry Canada. This office was disbanded in April 1988. New metric regulations were never introduced. Canadian metrication efforts had official stalled.On 4 November 1993 the Liberal party formed a new majority government under Jean Chrétien. Today in Canada the prominent retail measurement system is British imperial with metric either added as an afterthought or absent altogether. The only exception is the retail of deli products which are, for the most part, sold by the 100 g unit to make prices appear less expensive.

"Lately, I've noticed vehicles with tires that are clearly not OEM (Original Equipment Manufacturer) in size."

How can that be? If the manufacturer of your original tires is Goodyear then Goodyear makes tires in all sizes. All tire sizes offered by Goodyear would be OEM (Original Equipment Manufacturer, who we have used Goodyear as our example).

By and large these days the OE (Original Equipment) tires are on the large size. Or at least large by past standards. I have seen no need to deviate. Have seen friends restore good ride and handling by removing oversized tires and wheels installed by previous owners.

Kid next door put something like $2000 of 24's on his $1000 car and destroyed the transmission because it was geared so high. Managed to sell/trade his wheels for a rebuilt transmission which he wouldn't have needed in the first place but for the wheels.

Hello Das & BT1288. BT, you're among the few who understand what these number mean and it is good to know. Das also has this knowledge, but sometimes when posting, errors are made. For those who don't want to deal with millimeters and percentages when computing tire height and width, there are calculators available on the Internet and a very good one on tirerack.com. I know both of you remember the days of letters on the sidewalls. This new system provides more information but adds confusion to some, especially when you are dealing with metric measurements.

One addition to your post, BT, is that tire height greatly modifies ride behavior and handling issues. With a low profile tire, there is less give in the sidewalls to absorb road variations. I ordered the standard tires when I purchased my 2012 Chevrolet Sonic for this reason. It was also reported in several car magazines regarding this particular car. I'm not disappointed.

Hi Das. I have a question. Is Montreal entirely metric? My wife was a missionary in Canada and between metric math and French, she had a time mastering these issues.

Das Auto said "What is the real size? 185/75/14 or 195/75/14? If your passing this way i have a set of 4 195/75/14 in my back yard lolThe difference of a 70 series to a 75 series is minimal,in width.And will not affect your speedometer.Going from a 185 to a 195 will change approz 2 mph. as the 195 is a taller tire.These sizes are still common to purchase. ..You've got it backwards Das, the first number, 195 is the tread width, 60, 70 etc is the percentage of sidewall height compared to width. On my 315/35/17's, the 315 is mm width, it has 35% sidewall height compared to width of the tire.The width doesn't effect the speedometer, height does.

My daughter's 92 Jetta comes with 175/70/13 stock size.For the winter i installed 185/60/14 winter tires.When the summer rolls around i will install 92 Passat rims 15" and tire size 195/50/15 front and 205/50/15 rear, with room to spare.My son ran a set of 17" rims on his 92 Golf....lottsa tire.As for the difference in the speedo not sure but no tickets so far.

jimmy544:The tires were 185-195 R 75 size and now the closest you can get is R70:

What is the real size? 185/75/14 or 195/75/14? If your passing this way i have a set of 4 195/75/14 in my back yard lolThe difference of a 70 series to a 75 series is minimal,in width.And will not affect your speedometer.Going from a 185 to a 195 will change approz 2 mph. as the 195 is a taller tire.These sizes are still common to purchase.

Yes when possible. The tires that Volvo recommended for the 240 models you have a hard time finding these days. The tires were 185-195 R 75 size and now the closest you can get is R70 in the same width. They work pretty well but they are slightly smaller and throws off the odometer speedometer a little.

Rumbleseat said, "Many cars from the 1990s and newer don't have the clearance to go to a much wider tire. My Ford, for instance, 1 size up would rub, same with my Suzuki. My wife's old Ford was good for 1 upsize, 2 would rub.Cars from the 50s had room to upsize and still hold a party in the wheelwell.

So I have stock size tires, but very highly rated all-seasons which trade off to very highly rated winter tires. There isn't much reason for me to want to change sizes anyway...."I don't know what you mean by 1 upsize or 2 upsize, that's pretty funny. My 94 Mustang came with 225/55/16's and I upgraded to 315/35/17's on the rear, that's right, 95 mm wider, with no rubbing, the tires don't stick out of the wheelwell, and they're the same diameter so the speedometer is not affected, it's all about backspacing, offset of the wheel and sidewall height. So much misinformation in this thread.

Many cars from the 1990s and newer don't have the clearance to go to a much wider tire. My Ford, for instance, 1 size up would rub, same with my Suzuki. My wife's old Ford was good for 1 upsize, 2 would rub.Cars from the 50s had room to upsize and still hold a party in the wheelwell.

So I have stock size tires, but very highly rated all-seasons which trade off to very highly rated winter tires. There isn't much reason for me to want to change sizes anyway.